Evolution of layered yttrium hydroxide nitrate particles during controlled double-jet precipitation

Abstract

Layered yttrium hydroxide nitrate particles Y2(OH)5(NO3)·xH2O (LYH) were synthesized by controlled double-jet precipitation (CDJP) in the pH range of 7–9.5. The pH value and the duration of precipitation, have a significant effect on the morphology and growth behavior of LYH particles. Spheroidal particles with a radial arrangement of straight polycrystalline plates were prepared at pH 7. The alignment and ordering of crystallites decreases at pH 8, which leads to the growth of many branching sheets that form huge spheroidal networks of LYH particles. During precipitation at pH > 8, irregularly shaped LYH agglomerates continuously form with a wide range of sizes. An assumption has been put forward about the decisive role of the two-step mechanism of nucleation/crystallization of LYH. The results of the study provide a simple way to prepare uniform spheroidal LYH particles promising for the production of functional oxide powders and ceramics.